1. Field of the Invention
The present invention relates to a plastic molding unsealing apparatus used for examination or quality check at a time of inferiority analysis by dissolving and removing a portion of a plastic molding such as a semiconductor chip, a condenser, a hybrid IC, or the like which has been sealed by plastic.
2. Description of the Related Art
Conventionally, there is known a plastic molding unsealing apparatus which dissolves and removes a portion of a plastic molded sample, such as a semiconductor chip, a condenser, a hybrid IC, or the like which has been sealed or encapsulated with plastic, by chemical liquid for exposing.
Among the conventional plastic molding unsealing apparatuses, there is conventionally one which unseals the sample using nitric acid. In the case of using nitric acid, since nitric acid does not corrode aluminum material used in an IC circuit, an excellent result is obtained.
However, in recent plastic moldings, ones which can not be dissolved by nitric acid have been rapidly increased, and concentrated sulfuric acid which has been heated at a high temperature is being used on such samples. In a plastic molding unsealing apparatus using such a heated concentrated sulfuric acid, the heated concentrated sulfuric acid is supplied to an unsealing processing portion of the plastic molding unsealing apparatus, and it is injected to a portion of the sample to be unsealed, thereby unsealing the portion.
In such a conventional art, however, since sulfuric acid is used, there is a problem that, in a case where the sulfuric acid contains water or moisture, aluminum material used in an IC circuit corrodes when the sulfuric acid contacts the IC circuit. Furthermore, another problem is that sulfuric acid itself has strong water absorbability and it absorbs moisture in the air when the sulfuric acid contacts the air in an unsealing processing.